1. Field of the Invention
The present invention relates to a physical sensor for measuring a force, a pressure, a torque, a velocity, acceleration, a position, a displacement, an impact force, a weight, a vacuum degree, a rotation force, a vibration, and the like.
2. Discussion of the Background
Previously, as a means for measuring a force, a pressure, a torque, a velocity, acceleration, a position, a displacement, an impact force, a weight, a vacuum degree, a rotation force, a vibration, and the like, a physical sensor for measuring a dynamic change via a strain (stress) has been widely utilized. As this physical sensor, generally, an device constructed by utilizing a piezoresistive material has been used.
Piezoresistance refers to phenomenon in which an electrical resistance of a material is changed when a compression stress, a tensile stress, a shearing stress, or a hydrostatic pressure, etc. is applied to a material.
A physical sensor is obtained by baking a piezoresistive paste onto a diaphragm or beam comprising a metal, zirconia, and the like. In such the physical sensor, a physical parameter is measured by adding strain to a diaphragm or beam from the outside, and detecting a variation of this electric resistance.